Airplane-screw



C. A. DE GIERS.

' AIRPLANE SCREW.

APPLICATION FILED OCT. 23.1917.

Patented July 12, 1921.

Ill

INVENTOH dd A TTOR/VEY UNITED STATES I PATENTI' OFFICE.

CLARENCE A. m4: arms, or KEYIOR'I', NEW JERSEY, ASSIGNOR 'ro WILLIAM BARKER, or NEW BRIGHTON, NEW YORK.

manner AIRPLANE-SCREW.

Specification of Letters Patent. I Patented J l 12, 1921.

Application filed October 23, 1917. Serial No. 198,017.

To all whom it may concern Be it known that I, CLARENCE A. DE Gums, a citizen of the United States, and a resldent of'Keyport, in the county of Monmouth, and State of New Jersey, have invented certain new and useful Improvements in Airplane-Screws, of which the following is a full, clear, and exact descrlptlon, whereby any one skilled in the art may make and use the same.

The invention relates to so-called alrplane screws or propellers to be made in composite form and as a single unit structure to overcome existent objections to the wood or metal propellers in common use.

The object of the invention 1s to provlde a composite structure which, from blanks may be assembled and molded by heat and pressure into a finished unitary structure.

In a co-pendin application, Serial No. 198,018, filed October 23rd, 1917, I have described and claimed a propeller, of the general character herein referred to, which is' formed in a mold from a vulcanizable material as a unit structure. I

The present invention is directed to providing unitary structure through the agency of vulcanizaton, but with certain features of armoring and filling to enhance the value of such a structure, at the same time reducin the cost of construction and providin f or lightness and stability.

Re erring to the drawings:

Figure 1 is a view in elevation showing an outline of a propeller. v

Fig. 2 is a cross-sectional view.

Fig. 3 is a fragmentary view on a much enlarged scale as compared with Fig. 2, showing the structural formation.

Fig. 4 is a fragmentary view illustrating the laying of reinforcing materials.

Fig. 5 1s a sectional view adjacent to the fillet.

.Fig. 6 is a cross-sectional the form of Fig. 5. v

Fig. 7 is a cross-sectional view a modified form of fillet.

Wood propellers are well known and in common use for air and sea planes and, in fact are almost universally employed in preference to metal screws or propel ers.

It has been found that the metal propeller cannot be depended upon, owing to disintegration of the metal due to flexing, vi-

view through illustrating thin laminae of bratory actions, almost complete ood propellers have been successfully used, but their life is extremely short and there is an element of danger in their use. In the construction of wood propellers, they are formed from laminated wood, usuall mahogany and oak which are glued together to form a blank; This blank is then turned and carved to form and requires a great amount of hand labor to secure accurate dimenslons, surfacing, etc. It is, of course, ffilled, varnished, and rubbed down to give it the proper surface.

Such propellers, jected to the extremely high duty imposed upon them, soon wear and chip at their entering edges and, due to sand and water spray, arechipped at the entering edge and worn on the surfaces by the abrasive actions of sand and water spray. Obviously, as soon as the finish of the edge or surface is broken, they rapidly deteriorate as they are then subject to all the conditions of warpage and'deterioration due to climatic changes and entrance of moisture to the structure. There is also great danger in use of said propellers from splitting and flying apart. It takes comparatively little to destroy a wooden propeller. It becomes brittle and unfit for use in a short time due largely to the fact that it is im ossible to build up a structure having perectly matched graining of the wood, free from sap grain, dry rot, and other faults. Such faults are hardly distinguishable,

material, and it is almost a physical impossibilitiy to insure perfect gluing of the parts.

Furthermore, the compression of the fiber at the hub when such propellers are applied distorts the fiber and as such a propeller is constantly under enormous strains, both torsionally and throu h its flexing to say nothing of the centri ugal action, this distortion of the fiber at the hub re-acts on the fiber throughout the structure, causing numerous breaks of the blades adjacent to the hub. This breakage has, by some, been-ateven in the comparatively.

tributed to the centrifugal action which throws. the inherent life-giving moistures 1 To overcome the objections hereinbefore noted,'the presentI'invention contemplates the formation of a propellerfinished as to its ex terior with a vulcanizable material and having said-material arranged about and inclosingacore orfillet. v This construction givesthe advantage of providin propellers at a min f mum cost, as regards mshing of the article;

- or disintegrate, I

edges and surfaces are chipped or abraded.

' gives uniformity; and provides a surface and material which will not split, run in fractures, even though its entering eferring to the drawings,'the numeral 1, denotes the hub ,2, 3, the blades of'the propeller, which blades haveentering edgesfl,

5, and shanks 6, 7.

The mter r or central, portion of the propeller'consists of a'blank 8, having the general contour of the blades and hub and pref- 'erably perforated to permit a joiningof the covering material at points throughout the structure.

' and arrangement so 7' laid into the mold about the fillet and-the whole is then put *under compression and: vulcanized in the usual manner by applylng 40 tions as extendthrough the fillet. This arrangement has the advantage of preventing covering fformed Asillustrated in 5, there are series of perforations 9, formed through the fillet piece 8, which, as illustrated, is of a thin weblike' structure which may be of metal or other material to give stiffness and stability to the taller and yet be sufficiently flexible to ro ger orm its usual functions'when the propeller is under duty and is flexed. About this fillet 8, is arranged a vulcanizable material 10, which may e varied as to its form long as it, provides a sufliciently hard finished surface for the propeller.v

' In practice, the vulcanizable material 1s heat until saidvulcanizable material takes the form of the mold and is hardened about the fillet. i

It is obvious thatfthe material under vulcanizationwill extendthrough the perforations or'openings of the fillet piece and form a firm structure, united by such porbreaking away of the vulcanizable materia from the fillet exce t in restricted. areas.- For instance, prope lers which are under; gunfire might-be struck andgchiplped but there would be no considerablebrea of the total structure. 7

In Figs. 2 and 3, there is illustrated an ar-. rangement of securing a very efiicient covering for the fillet in which the fillet8, is completely surrounded and vulcanized into a of strata of material of ngdown different characters. For instance, there 1 a may be a'hard rubber compound 11, for the.

exterior; a softer compound 12, intermedii -at e..the hard compound; and a fabric 13. This may be alternated to give a composite vides a safeguardagainst pittin or shattering at the shanks o the blade, fand yet permits formation of a single piece structure from a mold without requiring a tremendous amount of hand labor and nstructurewhich will readily vulcanize to the desired hardness. v

i In Fig. ,4; there is illustrated at 14, an inlaying of cording ormetallic i i hi when vulcanized in as a layer of' inclosing material, will tend to stiffen and strengthen .the structure and'overcome the danger of breakage through the action of torsional and warping strains.

- A comparatively lightweight metal may be employed as. a fillet, but the by the'resilient vulcanized covering 1 so that it will not'deteriorate as the cutting edges and surfaces of the blades are abraded or pitted" from-the many causes which afiect propellers.

V In other words, the wood fillet is completel and perfectly concealed in and rojtecte so that its glued-up portions (if it be made oflaminatedwood) will vnot break loose, and there will be no opportunity for it to splinter and shatter.

' The life of such propeller, even with a wood fillet, is much greater than that of the ordinary. wood propeller, and it has the .'ad-

vantages of resisting the hard conditions of wear and will not split and fiy apart.

The covering may bearranged 'over the fillet in any desired manner, although the preferred method is to arrange blanks of the material cut to proper form which will be imposed one upon the other in the mold and the blanks are then vulcanized together.

As is described in my coending application, Serial No. 198,018, led October 23, 1917, the propellers may be formed by providing a mold approximately the size and shape of the pro eller, Whichmold is provided with a so t metal lining capable of being scraped to give the exact form and finish requlred on. the-finished article. The blanks are of vulcanizable material, and the fillet pieces are then laid into the mold and the wholeyis compressed and subjected to vulcanizing heat. j 'The arrangement herein described probreaking,

ishing upon the individualdevices. .What'lyclaim as my invention and desire to secure by Letters Patent is:

1. An aeronautical propeller, consisting "of a complete finished structure com risin a fillet completely inclosed in a; s ell o vulcanizable materlal.

2. An aeronautical propeller, consisting of a complete finished structure comprising a fillet completely inclosed in a shell of vulcanizable material and means permitting portions of the vulcanized material to become embedded in the fillet for securing such material and the fillet.

3. A propeller formed as a complete structure from a vulcanizable material vulcanized about a fillet, said fillet having the general contour of the finished propeller and provided with openings, said vulcanizable material extending through said openings to form areas of homogeneous material through the finished propeller.

4. A complete propeller consisting of a fillet having the general outlines of the finished propeller and a vulcanizable covering surrounding said fillet and vulcanized thereupon and joined at intermediate points through said fillet, the fillet having openings to permit the passage of the vulcanizable material.

5. A propeller consisting of a fillet having the general contour of the finished propeller, and laminae of vulcanizable material completely inclosing said fillet and vulcanized thereto and therethrough.

6. An aeronautical propeller comprising a core of relatively light and strong fibrous material and an inclosing shell of rubber vulcanized to and integrally united With said core.

7. An aeronautical propeller comprising a core of laminated Wood and an inclosing shell of hard rubber vulcanized to and integrally united with said core.

CLARENCE A. on GIERS.

Witnesses:

WM. B. HILL, EDITHJ. RnMoND. 

